1. Field
The present application is related generally to a data processing system and in particular to a method and apparatus for real-time polars. More particularly, the present application is directed to a computer implemented method, apparatus, and computer usable program code for providing real-time performance models for vessels.
2. Background
A ship polar or sailing polar is a model of a vessel's theoretical performance. Performance in this context is defined as a vessel's progress into the wind, also referred to as velocity made good (VMG), given the angle of the wind in relation to the bow of the vessel. The ship polar, also referred to as a performance model, provides predictions of a ship's speed based on weather conditions and ship heading.
Generally, users have to purchase files of sailing polars or manually create sailing polars from pre-recorded data. Polars are sometimes generated using U.S. Sailing's Velocity Prediction Program (VPP). The Velocity Prediction Program creates sailing polars based on vessel characteristics, such as hydrostatic analysis, stability analysis, body plan outlines, and lines processing. The results generated using these pre-generated, static polars do not generate results based on the actual performance of a particular vessel for which the polar is being used. This approach may be referred to as an off-line approach.
Another current solution is to produce polar diagrams based on wind speed, wind angle, and velocity made good. Those recordings are processed off-line using least mean squares fit. Polars may also be created manually by plotting velocity made good, true wind angle, and apparent wind angle values using currently available applications for creating polars. However, manually plotting polars may be unduly burdensome and inconvenient for a user.
Off-line techniques for creating polars use data regarding a particular vessel's expected or typical characteristics and recordings of weather conditions versus the expected performance for that type of vessel under the given set of weather conditions to pre-generate polars in an off-line or static approach. Sailing polars created using current solutions do not enable polars to account for real-time changes in a particular vessel's performance during an actual voyage. Thus, sailing polars, whether purchased by a user or manually created by the user, typically provide only a crude model of a ship's performance due to real-world variations in vessels, wear and tear, and other factors that may affect the performance of a particular vessel.